//import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;

import java.sql.PreparedStatement;

// 通过这个类来完成和数据库的连接
// 建立连接需要使用 DataSource,并且一个程序有一个 DataSource 实例即可，此处就使用单例模式来实现
public class DBUtil {
    private static DataSource dataSource = null;

    private static DataSource getDataSource() {
        if (dataSource == null) {
            dataSource = new MysqlDataSource();
            ((MysqlDataSource)dataSource).setURL("jdbc:mysql://127.0.0.1:3306/MessageWall?characterEncoding=utf8&useSSL=false");
            ((MysqlDataSource)dataSource).setUser("root");
            ((MysqlDataSource)dataSource).setPassword("1234");
        }
        return dataSource;
    }

    public static Connection getConnection() throws SQLException {
        return getDataSource().getConnection();
    }

    public static void close(Connection connection, PreparedStatement statement, ResultSet resultSet) {
        if (resultSet != null) {
            try {
                resultSet.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (statement != null) {
            try {
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}
